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Preferred gap

  • .032

    Votes: 1 4.5%
  • .030

    Votes: 11 50.0%
  • .028

    Votes: 5 22.7%
  • .026

    Votes: 3 13.6%
  • .025

    Votes: 2 9.1%
  • .024

    Votes: 0 0.0%

  • Total voters
    22
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Discussion Starter #1
I been messing with my spark plug gaps lately. Truck seemed to not be great at .030, so i've been incrementally moving it closer since I have 2 sets of plugs. What is the "hot zone" on some of your un-tuned 3.5L trucks? I'm also talking using Motorcraft plugs, the forum recommended ones.

I made it down to the .024-.025 range and my truck doesn't like that :rolleyes: Seemed pretty good at the .026-.027 range, guess I got greedy and figured I had to take it to the point it regressed. The .024 set did alot of pinging when I got on it, real smooth when barely on it town driving.

Looking forward to some opinions.
 

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Discussion Starter #2
Just got back from my test [email protected] .026 and i'm definitely happy with it for stock, no tune. Idle is much better, throttle response is there, and it has good power through the mid range now where it was only good low end. I'm curious to see if this is trend of where it should be, individually based, or why i'm so much lower than what stock recommends.

All in all i'm very happy with the step forward i've made on this truck by just a small adjustment and a little time and testing.
 

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@Grim Reaper runs his at .026, and this change I'm at .026 with my 2.7. That's my favorite so far. Grim is tuned, but I've run tuned and not *with my 2.7 on this gap.

Sent from my Moto G (5) Plus using Tapatalk
 

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I haven't gapped the plugs on my truck yet but my experience with previous turbocharged gas engines (2.3L Lima) is go as tight as possible. But this was back in the day's of copper plugs which was lucky to get 15k miles of life if even that.
 

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Discussion Starter #5
Makes me wonder if my truck is stock or not... Ran like horse ass in comparison when at .030. .026 is very smooth, and i'm happy I took the time.

Good info guys!
 

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I'm at .026" with a tune.
 
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Experiment and use whatever gap runs best on your engine. As a rule, turbo engines generally prefer tight gaps than Naturally Aspirated vehicles. This is due to the pressures inside your cylinder when under boost.

Most guys will find a gap somewhere between .025" and .030" is where their engine runs best. Though I recall a few guys running as low as .022".

Getting at our plugs are EASY (compared to a lot of other engines I have owned). So do not be afraid to do experiments.

Finally, I have found on a couple of plugs, that the gap seem to widen over time. This is why most guys recommend checking/changing your plugs once a year. Hell, it's a lot better than the old days (with 60s & 70s cars) when I had do a plug & point change every 3 months to keep the engine running optimally.
 

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How are you guys gapping your plugs? Do you bend the electrode? Do they come pregapped in smaller increments?
 

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How are you guys gapping your plugs? Do you bend the electrode? Do they come pregapped in smaller increments?
I have been using the Accel copper plugs that are one step colder and they come with a really tight gap so all i need to do is increase it to whatever I want and dont worry about having to close it.
 

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I might pull the plugs in the near future to check the gap. If I do I'll adjust to 0.026. Maybe it will get rid of the rough idle under certain conditions using 87/89 octane fuels.
 

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Discussion Starter #15
I might pull the plugs in the near future to check the gap. If I do I'll adjust to 0.026. Maybe it will get rid of the rough idle under certain conditions using 87/89 octane fuels.
I'd go small increments, and get a decent sample size. When I was doing increments, I got down to .024 and it was pinging when I went past 1/4 throttle. Went back up to .026 and it's money still 350 miles later.
 

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I'd go small increments, and get a decent sample size. When I was doing increments, I got down to .024 and it was pinging when I went past 1/4 throttle. Went back up to .026 and it's money still 350 miles later.
Thanks. Since I have the 2.7L the plugs should already be gapped to 0.028 so 0.026 would be the next logical step. :)
 

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Discussion Starter #18
Just to add to the thread, swapped out my Motorcraft iridiums for Autolite XP Iridiums today, starting the gap probing all over on these at .032. I'm aware most people here prefer the Motorcraft, I just wasn't that impressed. None of mine were cracked or anything, have new boots on the coils, used the goop every time. We'll see. The thread length on the autolite were about 1/16" shorter than the motorcraft. Not sure if that has an affect, just thought it was worth noting.
 

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Just to add to the thread, swapped out my Motorcraft iridiums for Autolite XP Iridiums today, starting the gap probing all over on these at .032. I'm aware most people here prefer the Motorcraft, I just wasn't that impressed. None of mine were cracked or anything, have new boots on the coils, used the goop every time. We'll see. The thread length on the autolite were about 1/16" shorter than the motorcraft. Not sure if that has an affect, just thought it was worth noting.

I know its been awhile, but how do you like the autolites? About to swap my second set of motorcrafts out for them.
 

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Discussion Starter #20
Still prefer over Motorcraft. 10K miles on them so far.
 
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